People attending events such as cultural, entertainment, or sporting events often find themselves located so far from the action that binoculars are required to be able to see adequately. Many people attending such events find carrying binoculars inconvenient, or simply forget to bring binoculars. Hence it is desirable that binoculars be made available for purchase or rent at such events.
Because of concerns about stock loss, hygiene, and administrative convenience, selling binoculars is preferable over renting binoculars at such events, even though the binoculars are likely to be used only once. The prior art is replete with examples of collapsible, folding, and wearable binoculars, such as those shown in U.S. Pat. Nos. 4,913,538, 4,913,541, and 4,986,644. Prior art binoculars generally include complex metal or plastic structures and therefore are unsuitable for a one-time use application. Moreover, the prior art collapsible and foldable binoculars in their collapsed states are often bulky, and have a format that makes them inconvenient for vending at an event.
The applicant is also aware of so-called paper binoculars, in which lenses in lens adapters are mounted in a complex structure formed from a piece of medium-weight card that is appropriately cut, folded, and glued. The card structure has two states, a relatively flat state for vending and carrying, and a 3-dimensional state in which the structure disposes the lenses relative to one another to provide fixed-focus binoculars.
The Galilean telescope, using a convex lens with a relatively long focal length as an objective lens, and a concave lens with a relatively short focal length as the eyepiece lens, forms the basis of most known collapsible, folding, and wearable binoculars. This arrangement requires only two optical elements to provide an erect magnified image, and is relatively compact, since the lens spacing is less than the focal length of the objective lens.